1. Technical Field
This invention relates to electrical wiring and, more particularly, to power cords of the type that can supply energy to devices such as engine block heaters.
2. Discussion
Two or more engine block heaters are often used in truck engines to elevate temperatures of fluids in the engine during cold weather. Sometimes only one heater is used but it is usually wired in series with a thermostat that automatically regulates the on/off cycle of the heater. In either event, power must be supplied to the devices.
FIGS. 1 and 2 illustrate a conventional prior art technique for supplying electrical power to a pair of such devices. A Y-shaped power cord 10 includes an electrical plug 12 at one end of a pair of wiring cables 14 and 16. The opposite ends of cables 14 and 16 include female connectors 18 and 20, respectively. Connectors 18 and 20, in turn, are connected to engine block heaters 22 and 24, respectively, and supply electrical power to them.
While these so-called "Y-cords" have generally proved satisfactory, they have caused some economic problems to the cord manufacturer and, to a lesser extent, to the truck fleet owner or manufacturer who may own or make a variety of different trucks. This is because the spacing between heaters on one engine is often different from the spacing of the heaters on another type of engine. The distance to the electrical outlet may also differ from chassis to chassis. It is, of course, imperative that the power cord be long enough to reach each heater but it is also preferable to avoid any excess length in the cord. If the cord is longer than needed this can result in excess power loss from the energy source, not to mention the cumbersomeness of having to deal with excessive lengths of cable lying around.
In an attempt to obviate these problems, a large number of custom made Y-cords having different lengths were created. This solution unfortunately requires that the cord manufacturer produce and the truck fleet owner/manufacturer inventory a wide variety of different Y-cords, each having their unique product codes. In addition, some customers may want the two end connectors to be wired in series instead of parallel, thus, further aggravating the situation. This situation often arises when an owner wants to retrofit his vehicle with a thermostat controlled heater.